textproduct: Albany

WHAT HAS CHANGED

Tornado Watch 352 in effect through 3 PM this afternoon for most of eastern NY excluding Ulster/Dutchess Counties and Litchfield County in NW CT.

Regional radars depicting low topped line of thunderstorms already across central NYS. Instability will increase east of the line where higher dewpoints and some breaks of sun are developing. Unusually strong low and mid level wind fields are allowing for strong low level helicity, with SRH values of 250-400 m2/s2 east of the approaching line.

As the line continues tracking east, some additional intensification is expected, though overall should remain low topped given strong mid level cap. Potential embedded rotating cells within the line of storms are possible. Also, damaging straight line winds are expected across a larger area given aforementioned wind fields and steepening low level lapse rates.

Will have to watch for possible expansion of current watch into Ulster/Dutchess/Litchfield Cos, where coverage is expected to be more limited, however any cells could become discrete and still have rotation.

KEY MESSAGES

1) A strong area of low pressure passing by to the north will bring windy conditions today, which could result in some downed tree limbs and power lines.

2) There is Slight Risk for severe thunderstorms for much of the region ahead of a cold front, with damaging winds being the main threat, though an isolated tornado can not be ruled out.

3) Mainly drier and non-impactful weather is expected for Father's Day weekend, although a few passing light rain showers can't be ruled out for northern areas.

DISCUSSION

KEY MESSAGE 1...

A strong area of low pressure (currently around 992 mb) is located over lower Michigan and it will be moving east-northeast across southern Ontario and southern Quebec for today. Ensembles and operational model guidance suggests this low will continue to deepen to around 988 mb or so, which is about 3-4 STD below normal according to the 12z NAEFS.

This will result in an unusually strong pressure gradient over the region for mid June. This setup, more typical of the Fall or Winter, will result in strong south to southwest wind gusts ahead of the storm system for today, with winds becoming westerly by this evening. A Wind Advisory continues to northern areas for today. While gusts may fall short of typical advisory-levels, gusts in the 30-45 mph range will result in some downed trees and power lines, as fully leafed-tree limbs will fall easier than in the cool season. A few gust may top out around 50 mph or so, mainly for the Capital Region. Some power outages can be expected today due to the downed tree limbs, so the Wind Advisory is justified even though widespread gusts of 46 to 57 mph aren't expected. The strongest gusts are expected from the late morning through early evening hours.

KEY MESSAGE 2...

Although some showers and a few rumbles of thunder are expected first thing this morning thanks to a passing warm front, there will be the potential for a round of stronger thunderstorms during the late morning through late afternoon hours, as a broken line of convection may develop ahead of a strong cold front. Enough clearing may occur behind the early morning rain for some instability to build across the area. Dewpoints will be surging into the 60s behind the departing warm front and daytime temps will rising through 70s and even reaching the low to mid 80s in valley areas from the Capital Region southward into the mid Hudson Valley.

The latest 3km HRRR suggests that SBCAPE may reach 500-1000 J/kg, although this will ultimately depend on how much clearing occurs. With plenty of shear (0-6 km bulk shear values in the 50-60 kt range) and helicity (0-1 km helicity values in the 100-300 m2/s2) in place, there are the dynamics available for strong storms, although if enough instability is available will be the main question. Based on the latest CAMs, it does look like a low topped line of convective may be able to develop for the late morning and into the afternoon and will move west to east across the area. Damaging wind gusts will be the main threat, although cannot rule out a brief tornado, especially considering SigTor values are projected to the in the 1 to 2 value range. SPC now has areas northeast of the Capital Region in a 5% contour for tornadoes, which makes sense considering the CAMs.

The threat for severe storms will lower early this evening as the front moves west to east across the area.

KEY MESSAGE 3...

For Friday into the weekend, a broad, but shallow upper level trough will be in place over the Northeastern US. There could be some cyclonic flow light rain showers during the diurnal heating, mainly for the Adirondacks and southern VT, each day during the afternoon and evening hours. Otherwise, skies will be partly cloudy across the region and impactful weather is not anticipated. Daytime temps will be a little cooler than Thursday, but very comfortable and still near or just slightly below seasonal normals, with mid 70s to low 80s in valley areas. Lows will generally be in the 50s, although some 40s can't be ruled out for the high terrain. Daytime dewpoints will be comfortable in the 50s as well.

AVIATION /14Z THURSDAY THROUGH MONDAY/

Light rain is currently impacting the TAF sites and this rainfall will be exiting off to the east over the next few hours. Within the light rain, flying conditions will be MVFR. This precip should mostly be down around 14z, although it may take another hour or two for ceilings to fully return to VFR.

Ahead of a cold front, some scattered thunderstorms are expected for this afternoon and will include a PROB30 for all sites for this activity. Within thunderstorms, visibility could lower to IFR and gusty westerly winds could exceed 40 kts. Any thunderstorm would be brief and last under an hour, but could be strong to severe. Otherwise, it will be VFR with bkn cigs around 4-6 kft.

The threat for storms will end by the early evening hours, but some lingering clouds at 3-4 kft will continue into tonight, but flying conditions should generally be VFR.

The other aviation impact today will be strong gusty winds, even outside of thunderstorms. Southerly winds are currently around 5-10 kts (slightly higher at KALB). These winds will increase to 10-15 kts through mid-morning with some gusts in the 20-30 kt range. For the mid-morning into the afternoon, sustained winds from the south to southwest will be 15-20 kts and some gusts will reach 30-40 kts, with the highest gusts at KALB. Winds will become westerly by evening and start to decrease, but even into tonight, westerly winds will still be gusting 15-25 kts at times. With the expected strong surface winds, won't include LLWS within the TAFs as there won't be much differential between the surface and 2 kft, especially during the daylight hours.

Outlook...

Friday Night: Low Operational Impact. Breezy. NO SIG WX. Saturday: Low Operational Impact. Breezy. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Low Operational Impact. NO SIG WX. Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: High Operational Impact. Likely SHRA...TSRA. Monday Night: Moderate Operational Impact. Chance of SHRA. Tuesday: Low Operational Impact. Slight Chance of SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Wind Advisory until 8 PM EDT this evening for NYZ032-033- 038>043-048>054-082>084. MA...None. VT...Wind Advisory until 8 PM EDT this evening for VTZ013-014.